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Creating Accurate Time Estimates

By Landerson

I recently joined a new project where I will be working as the person responsible for the developing and creating the requirements and documentation on a major development effort. As the person on the hook for a significant portion of work, I need to provide accurate time estimates for my portions of the project. I was concerned about providing accurate time estimates on a new project in a new environment. I am also very aware that deadlines are important and know that if I am unable to accurately estimate my deliveries, I will quickly lose credibility with the rest of the team. Underestimating my deadlines might also put other team members relying on my work at risk of missing their deadlines.

My concerns had me thinking that perhaps others might be in a similar situation. After a bit of research and analysis of my own process I compiled the following list of questions and suggestions to help when making time estimates.

  1. How accurate do your time estimates need to be?
    If an estimate needs to be very accurate, it is usually a good idea to take a longer period of time to consider and analyze the answer. It is not unreasonable to ask someone who is looking for a timeline for some “think time” in order to provide an accurate answer. However, when not immediately responding, it is a good idea to communicate a reasonable target for when you will have the estimates finished, even if it’s only 15 minutes of extra think time.


  2. How well do you fully understand the project/tasks that you are being asked to estimate?
    If a problem is complex, or if you do not completely understand all of the tasks you need to finish, it will be difficult to make accurate time estimates. Getting as much clarification as you can is necessary. Discussing the details of what you have been asked to accomplish with the person making the request might also provide them insight into the complexity of the request and your work process.


  3. How long has a task of this type taken to accomplish in the past?
    It is a good idea to maintain a personal log of tasks and an ongoing list of recorded time spent performing a task. I simply use an excel spreadsheet to record tasks I have finished on my projects and update it when I have a few moments at the end of the day or week. Having a realistic idea of the amount of time I spend on my tasks helps me to accurately predict future projects/tasks.


  4. Are there any assumptions, conditions or constraints which might affect your time estimate?
    It is impossible to predict in advance every detail of a project with certainty. It will be important to note your assumptions and constraints when you provide your time estimates to communicate your issues clearly. These could all be considered risks to the accuracy of your time estimate and should continue to be monitored as you begin the tasks/project.


  5. Do you need to add any wiggle room?
    You should consider adding contingency time if there is a lot of uncertainty about the tasks or many risks associated with your estimate. By increasing time to the estimate appropriately because a project is new and unfamiliar as a way to prevent underestimating your efforts.


  6. Are there any other elements to the project/tasks that should be included in your time estimate?
    One area I consistently forget when creating estimates is the amount of extra time I have to spend doing administrative tasks like organizing meetings, sending emails, or organizing documents. At times, these types of activities are not always predictable, but understanding how much of your work might be effected by other project duties is important. There is a small amount of extra administrative work in most tasks, and adding that into your work estimate will help your estimating efforts.

When I employ these methods they have lead me to more accurate time predictions that have also greatly reduced my anxiety over creating self imposed deadlines that are unrealistic. As I also have an intrinsic desire to please the person asking for my time, using some standard processes in producing my time estimates has lead me to win/win situations for both my project and myself.

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This entry was published on Jun 25, 2010 / Seilevel. Posted in Business Analysis, Analytical and Problem Solving Skills, Technical Topics, Tools. Bookmark the Permalink or E-mail it to a friend.
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phillips31 posted on Monday, June 28, 2010 3:50 PM
I can understand that you would want to know how much time that you need in order to get your information back to the project team however I would believe that would be part of the delagation made the person or persons who sent you the information prior.

Assuming such information is considerable for the project completion and as far as moving the project forward.

At the same time , and this is just my biased opinion. I would have asked prior to my commitment to my side of the project when is the deadline. That is what my personal inate resposibility would have brought to this project.
Marc Thibault posted on Monday, July 12, 2010 8:51 PM
Accuracy isn't the issue. It's not how accurate the estimate is that's important. What's important are the odds of meeting or beating a given target.

"How long will it take" doesn't have one answer. It has a whole bunch of answers and each answer has its own probability of being right.

You're asking the right questions, but the result should be a probability distribution, not a guestimate that's guaranteed to be optimistic. The answers to your questions will establish a range of values and some sense of their relative probabilities. If you create a cumulative probability plot that reflects what you've found, you now have the means to ask the client how much risk they can tolerate and use that to set a target. The curve plots the probability of meeting or beating a date, plotted against the date. Pick a date, the curve tells you your probability of success; the later the date, the higher the probability of success. Or pick a probability of success and the curve gives you a target date.

If you choose the date without consulting the client and the probabilities, you're usurping your client's right to decide how much risk to take on.
Marc Thibault
Marc Thibault posted on Monday, July 12, 2010 9:03 PM
Oops! Sometimes my fingers run ahead of my brain.

For "client" read "project manager". It's the PM that has to talk probabilities with the client.
Marc Thibault
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